Character storage apparatus with individually replaceable, accurately located character fonts

ABSTRACT

This disclosure depicts character storage apparatus especially for use in a phototypesetting machine or the like for storage characters for selective presentation at a character display location, including a plurality of discrete character carriers each carrying a font of characters which revolve on a cylinder of revolution when the phototypesetting machine is in operation, the carriers being dimensionally rigid at least in the said cylinder of revolution. The apparatus includes carrier mounting means and means for attaching the carriers to the carrier mounting means such that the characters are located with extreme accuracy.

United States Patent [191 Tidd ]March 20, 1973 [54] CHARACTER STORAGEAPPARATUS WITH INDIVIDUALLY REPLACEABLE,

ACCURATELYLOCATED CHARACTER FONTS [75] Inventor: James Alfred Tidd,l-laverhill, Mass.

[73] Assignee: Graphic Systems, Inc., Lowell,

Mass.

[22] Filed: Aug. 30, 1971 [21] Appl No.: 176,222

[52] US. Cl. ..95/85, 95/45 R [51 Int. Cl. ..G03b 15/00 [5 8] Field ofSearch ..95/4.5 R, 85

[56] References Cited UNITED STATES PATENTS 3,485,150 12/1969 Tortoriciet a1 ..95/4.5 R

3,610,121 10/1971 Hanson et al. ..95/4.5 R

Primary Examiner-Samuel S. Matthews Assistant Examiner-Richard A.Wintercorn Atl0rney-R0sen & Steinhilper [57] ABSTRACT This disclosuredepicts character storage apparatus especially for use in aphototypesetting machine or the like for storage characters forselective presentation at a character display location, including aplurality of discrete character carriers each carrying a font ofcharacters which revolve on a cylinder of revolution when thephototypesetting machine is in operation, the carriers beingdimensionally rigid at least in the said cylinder of revolution. Theapparatus includes carrier mounting means and means for attaching thecarriers to the carrier mounting means such that the characters arelocated with extreme accuracy.

13 Claims, 4 Drawing Figures CROSS-REFERENCE TO RELATED APPLICATION Theapplication is related to, but is in no way dependent upon, copendingapplication Ser. No. 43,764 filed June 5, 1970, assigned to the Assigneeof the present invention.

BACKGROUND OF THE INVENTION One type of phototypesetting apparatuspresently in commercial use includes a character storage drum whichcarries on a film strip of plurality of character fonts arranged intandem around the periphery of the drum. The drum is rotated rapidly tobring the characters in sequence before an optical imaging systemilluminated by a quickly pulsed light source. A particular character isselected by causing the light source to be pulsed when that character isregistered with the imaging system. The end product of suchphototypesetting apparatus is a photographic printing plate.

In the practice of phototypesetting, as with all typesetting, a largenumber of type fonts are made available for selective use according tothe specifications of particular jobs. It is desirable thatphototypesetting machines have the capability of setting a characterfrom the greatest possible number of fonts with the least expenditure oftime and labor.

Many drum-type phototypesetting machines have the capability of storinga number of fonts in tandem around the periphery of the characterstorage drum; however, in general such machines require that the fontcombinations be pre-selected and placed on a master film strip which isthen secured on the periphery of the drum. In one commercially availablemachine, font interchangeability is provided by the use of film stripscarrying individual character fonts which are attached separately to theperiphery of a drum and aligned by means of registration pins.

However, the described arrangement for providing individual fontreplacement or interchange has a number of serious deficiencies. First,the accuracy with which the character fonts can be positioned and heldon the drum, initially and especially after a period of use, is notconsidered to be acceptable. The registration pins are necessarilymanufactured with significant tolerances, as are the apertures in thefilm which receive the pins. After a period of use, due largely tohandling and to the stresses induced in the film strip by high speedrotation of the strip, the apertures are apt to enlarge. Secondly, thedescribed arrangement for providing selective replacement of individualcharacter fonts is unnecessarily time consuming and laborious so much sothat in practice some users prefer to replace an asscm bled drum ratherthan to attempt to replace an individual font strip on the drum.Thirdly, it has been found that because of the dimensional flexibilityof a film strip is apt to bow, warp, or be otherwise distorted at highrational speeds. This is particularly serious when the effect is todistort the registration between the characters and associated timingmarks which customarily accompany the characters on a font strip. Thetiming marks are customarily monitored electrooptically by the machinescontrol center in order that the control center may be capable ofknowing which character is located at any given time at the characterdisplay position or station.

The problem of accurate location of the characters on the drum isparticularly acute in machines having the capability of magnifyingcharacters.

OBJECTS OF THE INVENTION It is an object of this invention to provide,for use in phototypesetters and other character display or recordingapparatus, improved character storage apparatus for storing charactersfor selective presentation at a character display station in theapparatus.

It is another object to provide character storage apparatus by which anyof a plurality of character fonts can be individually replaced orinterchanged with a minimum expenditure of time and effort.

It is an important object of this invention to provide a characterstorage drum including a plurality of discrete character carriers eachcarrying a font of characters, which characters are positioned and heldon the drum with a high degree of accuracy, not only initially but afterlong periods of use, as well.

It is still another object of this invention to provide characterstorage apparatus which provides a rigid backing for the storedcharacters so as to minimize the possibility of misregistrationoccurring at high rotational speeds between characters and theirassociated timing marks.

Further objects and advantages of the invention will in part be obviousand will in part become apparent as the following description proceeds.The features of novelty which characterize the invention will be pointedout with particularity in the claims annexed to and forming a part ofthis specification.

BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of theinvention, reference may be had to the following detailed descriptiontaken in connection with the accompanying drawings wherein:

FIG. 1 is a perspective view, partially exploded, illustrating characterstorage apparatus constructed according to the teachings of thisinvention;

FIG. 2 is a section view taken through drum segment 20 in FIG. 1;

FIG. 3 is a perspective view of an alternative embodiment of theinvention; and

FIG. 4 is a section view similar to FIG. 2, taken through the FIG. 3embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 12 illustrate characterstorage apparatus representing a preferred implementation of theprinciples of this invention. FIGS. l-2 illustrate a character storagedrum 10 intended for use in character display or recording apparatussuch as phototypesetters (including photocomposers) and the like,comprising a hub 12 and a plurality oflike drum segments l4, 16, 18, 20which are adapted to be attached to the hub 12. The drum segments 14,16, 18, 20 function as character carriers, each carrying a font ofcharacters 22. Whereas each drum segment is shown as carrying one fontof characters, it is within the purview of this invention that eachsegment carrying a number of fonts, for example, a pair of relatedfonts.

Whereas any of a number of means may be employed for disposingcharacters on the segments l4, 16, 18, 20 in the illustrated preferredembodiment the characters are recorded on a strip 24 of photographicfilm which contains, in addition to a font of characters 22, a row oftiming marks 26 associated with the characters 22 for providinginformation useful to a phototypesetting machine's control center indetermining the particular character which is located at a predeterminedcharacter display station at a given instant. For a description of theassociated system as a whole reference may be had to theabove-identified copending application, now U.S. Pat. No. 3,631,774.

Each of the drum segments 14, 16, 18, 20 includes a cylindrical portion28, the outer surface 30 of which supports the characters 22, and aradially extending web 32 connected to the cylindrical portion 28. Itcan be seen that the characters rotate on a cylinder of revolution whichincludes the outer surface 30 of the cylindrical portions 28 of the drumsegments. Each character is thus presented to the associated characterimaging system (not shown) at the same radial distance from the drumaxis, and consequently at the same axial position in the imaging system.

In order to provide room within the drum for a light source forilluminating the characters, the web 32 of each segment is connected tothe cylindrical portions 28 asymmetrically. It has been found that thisasymmetry causes a distortion of the drum at high rotational speeds. Tocounterbalance the drum, weights 34, 35 are added to the shorter side ofthe cylindrical portion 28.

It is an important object of this invention to provide character storageapparatus by which characters are stored at predetermined locations withhigh accuracy. The problem of accurate positioning of the characters onthe character storage apparatus has a number of facets. First, thecharacters must be positioned accurately along the axis of the drum,that is, with respect to an arbitrary reference plane oriented normal tothe axis of the drum. In the illustrated embodiment wherein thecharacters are arranged end-to-end, rather than sideby-side, any errorin the axial position of a character will result in a misplacement ofthe character on the photographic printing plate (not shown) in adirection along the line oftype.

The second source of error is in the timing of a character presentation(by the pulsing ofa light source, for example). Any error in timing of acharacter presentation will result in a misplacement of a character onthe printing plate high or low relative to the line of type. Whereas thetiming of character presentation is largely a function of the accuracyof the electro-optic monitoring system which senses and counts thetiming marks 26, it is important that the registration of the timingmarks 26 with the characters 22 on a particular drum segment bemaintained. Any significant distortion of this registration, such asmight be caused by centrifugal stresses induced in a loosely held filmstrip rotating at high angular velocities, is apt to introduce timingerrors. In accordance with this invention dimensional stability of thecharacters and associated timing marks, at least in a cylinder ofrevolution in which the characters and marks rotate, is provided so asto obviate any such timing errors.

In order to insure accurate axial placement of the characters, inaccordance with one implementation of this invention, a film strip 24carrying a font of characters 22 and associated timing marks 26 is veryaccurately adhered to the outer surface 30 of the cylindrical portion 28of each of the segments 14, 16, 18, 20, as by a patterned adhesive 36disposed on the back of the film strip 24 except in those areas whichcontain the characters 22 and timing marks 26. Commercially availabletwo-faced adhesive tape may be used as the adhesive binder.

Viewing this aspect of the invention in a broader sense, there isprovided by this invention a plurality of discrete character carriers,each carrying a font of characters which is disposed on a cylinder ofrevolution when the photocomposing machine is in operation, the carriersbeing dimensionally rigid at least in the said cylinder of revolution.Thus, it is within the compass of this invention to provide, forexample, a rigid backing for a font of characters which might be in theform of a transparent planar plate bent into a cylindrical shape andattached to a frame, hub, or other mounting means. Such a strip may beflexed to take a cylindrical configuration, yet be extremely rigid inthe cylinder of revolution in which it revolves, so as to preclude anydistortion of the synchronization of the characters 22 and associatedtiming marks during rotation thereof. Such a rigid character ascontemplated by this invention minimizes the problem of wear andconsequent loss of character positional accuracy such as plagues theconventional film strip arrangements presently in use today and in thepast.

In order that the characters, once placed accurately on a rigid carrier,may be positioned very accurately on the drum axis, according to thisinvention the segments 14, 16, 18, 20 are provided with an accuratelyformed mounting surface 37, here shown as being on the lower surface ofthe web 32, which is secured to an accurately machined, molded orotherwise fabricated mounting surface 38 on the hub 12. Zero clearanceclamping means, here shown as comprising a pair of springloaded screws40, 41 received in threaded openings 42, 43 in the drum segments, areprovided for clamping together the mounting surfaces 37, 38 of the drumsegments and the hub 12. Close tolerance alignment pins 44, 45 fittingin openings in the webs 32, one of which is shown at 46, minimizepositional variations in the location of the drum segments orthogonal tothe drum axis.

By this expedient, the segments can be attached and detached veryrapidly, and yet with extreme positional accuracy in the placement ofthe characters 22. Thus, rapid interchange or replacement of a font ofcharacters is made possible without any sacrifice whatsoever in theaccuracy of the axial positional placement of the characters. Alltolerances arising in the zero clearance clamping arrangement shown arein the dimensions of the pins 44, 45 and in the pin receiving openings46 in the drum segments. These tolerances exist only in the plane of thewebs 32 and are not effective axially. Thus, any variations in presentedcharacter placement which may result from such tolerances are realizedas variations in positioning of the character along the axis of thecharacter imaging system (not shown). Such variations as may result(e.g., 0.005 0.010 inch) are well within the depth of focus ofcommercially available optical imaging systems, and thus do not resultin any degradation of the ultimate photographic printing plate produced.

A plurality of L-shaped baffle members 47 are provided to bridge the gapbetween the film strips on adjacent drum segments and thereby tomaintain a normally dark condition for the electro-optic circuitmonitoring the timing marks 26 on the film strips 24.

Thus, by this invention character storage apparatus is provided whichpermits rapid and easy replacement of character fonts in order thatdesired combinations of character fonts may be easily and quicklyachieved. Further, this is achieved while providing and maintainingextremely high accuracy in the positioning of characters.

The preferred FIGS. l-2 embodiment illustrates the drum segments 14, I6,18, as being composed of a transparent plastic material, for example,optical quality acrylic. The use of a transparent drum enables thecharacter illuminating beam to be passed through the drum, permittingthe drum to be used as a rigid and dimensionally stable backing for thecharacters. For certain applications, however, a plastic drum may nothave the strength necessary to prevent unacceptable distortions.Accordingly, it may be desirable in such applications to provide a drumhaving greater rigidity.

FIGS. 3 and 4 represent perspective and cross-sectional views of analternative embodiment of the invention wherein the drum segments, oneof which is shown at 48, are composed ofa material having relativelyhigh rigidity, such as aluminum. Because aluminum is not transparent tolight, the cylindrical portion 50 of the segment 48 has an opening orcut-away 52, 53 in the areas registered with the characters 54 andtiming marks 56 of the film strip 58. As in the FIGS. 12 embodiment, anadhesive 60 may be employed to adhere the strip 58 to the outer surfaceof the cylindrical portion 50 of the drum segment 48.

Because the FIGS. 3-4 drum segment has much greater rigidity than theplastic FIGS. 1-2 embodiment, it is not apt to distort during rotationand the weights which were desirable to counter-balance the drumsegments in the FIGS. 12 embodiment are not necessary. In other respectsthan those discussed, the FIGS. 3-4 drum segment may be considered to belike the FIGS. l2 segments.

The invention is not limited to the particular details of constructionof the embodiments depicted, and it is contemplated that various andother modifications and applications will occur to those skilled in theart.

For example, whereas the FIGS. l-2 embodiment shows four drum segments,it is within the purview of this invention to provide a greater orlesser number of drum segments. As discussed above, the principles ofthis invention may be implemented in other ways other than the use of arigid drum segment having a cylindrical portion attached to a webportion; many other structures are contemplated some of which aresuggested directly above and others of which are obvious equivalents andalternatives to those described and suggested. Rather than forming thecharacters photographically on a film strip which is adhered to acharacter carrier, the characters could be formed directly on thecarrier by vapor deposition techniques or could otherwise be disposed onthe carriers.

Therefore, because certain changes may be made in the above-describedapparatus without departing from the true spirit and scope of theinvention herein involved, it is intended that the subject matter of theabove depiction shall be interpreted as illustrative and not in alimiting sense.

What is claimed is:

1. For use in a phototypesetting machine or the like, character storageapparatus for storing characters for selective presentation at acharacter display location, comprising:

a plurality of interchangeable discrete character carriers each carryinga font of characters permanently secured thereto and adapted to becylindrically disposed on a cylinder of revolution when saidphototype-setting machine is in operation, said carriers beingdimensionally rigid in said cylinder of revolution, and said charactersin said font being positioned in an unobstructed optical path within theboundaries of the dimensionally rigid carrier;

carrier mounting means; and

releasable means for attaching said carriers to said carrier mountingmeans, whereby said character storage apparatus is capable of carryingdesired combinations of individually replaceable and dimensionallystable character fonts.

2. The apparatus defined by claim 1 wherein said carrier includes a filmstrip on which is recorded said collection of characters, said stripbeing adhered to said outer surface of said member.

3. The apparatus defined by claim 2 wherein said character carriers eachinclude a radially-extending web portion connected to a cylindricalmember defining said cylindrical surface, wherein said carrier mountingmeans defines a radially extending mounting surface and wherein saidmeans for attaching said carriers secures said web portion of each ofsaid carriers to said mounting surface of said mounting means withsubstantially no play parallel to the axis of said cylinder ofrevolution 4. For use in a phototypesetting machine or the like,character storage apparatus for storing characters for selectivepresentation at a character display location, comprising:

a drum comprising:

a plurality of interchangeable, rigid, discrete drum segments forreceiving a like number of fonts strips, one on each drum segment,

hub means, and

means for attaching said drum segments to said hub means; and

a number of discrete font strips equal to the number of drum segmentseach strip carrying a font of characters; and

means for attaching said font strips to said drum segments, one on eachdrum segment, whereby said drum is capable of carrying desiredcombinations of individually replaceable and accurately positionedcharacter fonts, said font strips being positioned to place saidcharacters in an unobstructed optical path through the rigid drumsegments.

5. The apparatus defined by claim 4 including registration pin means onsaid hub means and associated pin receiving openings in said drumsegments for minimizing positional variation of said drum elementstransverse to said drum axis.

6. The apparatus defined by claim 4 wherein said means for attachingsaid drum segments provides for attachment of said drum segments to saidhub means each independently of all others.

7. The apparatus defined by claim 4 wherein said means for attachingsaid font strips to said drum segments comprises an adhesive coatingdisposed on each font strip in a pattern configured to avoid thecharacters on said strip.

8. The apparatus defined by claim 6 wherein said means for attachingsaid font strips to said drum segments comprises an adhesive coatingdisposed on each font strip in a pattern configured to avoid thecharacters on said strip.

9. The apparatus defined by claim 4 wherein said hub means defines aradially extending mounting surface for receiving said drum segments,wherein said drum segments each have a radially extending surfaceadapted to mate with said mounting surface on said hub means, andwherein said means for attaching said drum segments provides forattachment of said drum seg ments to said mounting surface withsubstantially no play parallel to the axis of the drum whereby tooptimize the accuracy in an axial direction of the location of saidcharacters on said character storage apparatus.

10. The apparatus defined by claim 8 wherein said hub means defines aradially extending mounting surface for receiving said drum segments,wherein said drum segments each have a radially extending surfaceadapted to mate with said mounting surface on said hub means, andwherein said means for attaching said drum segments provides forattachment of said drum segments to said mounting surface withsubstantially no play parallel to the axis of the drum whereby tooptimize the accuracy in an axial direction of the location of saidcharacters on said character storage apparatus.

11. The apparatus defined by claim 4 wherein said drum segments arecomposed of a transparent plastic material.

12. The apparatus defined by claim 10 wherein said drum segments arecomposed of a transparent plastic material.

13. The apparatus defined by claim 10 wherein said drum segments arecomposed of a metallic material and have openings therein registeredwith said characters.

1. For use in a phototypesetting machine or the like, character storageapparatus for storing characters for selective presentation at acharacter display location, comprising: a plurality of interchangeablediscrete character carriers each carrying a font of characterspermanently secured thereto and adapted to be cylindrically disposed ona cylinder of revolution when said photo-type-setting machine is inoperation, said carriers being dimensionally rigid in said cylinder ofrevolution, and said characters in said font being positioned in anunobstructed optical path within the boundaries of the dimensionallyrigid carrier; carrier mounting means; and releasable means forattaching said carriers to said carrier mounting means, whereby saidcharacter storage apparatus is capable of carrying desired combinationsof individually replaceable and dimensionally stable character fonts. 2.The apparatus defined by claim 1 wherein said carrier includes a filmstrip on which is recorded said collection of characters, said stripbeing adhered to said outer surface of said member.
 3. The apparatusdefined by claim 2 wherein said character carriers each include aradially-extending web portion connected to a cylindrical memberdefining said cylindrical surface, wherein said carrier mounting meansdefines a radially extending mounting surface and wherein said means forattaching said carriers secures said web portion of each of saidcarriers to said mounting surface of said mounting means withsubstantially no play parallel to the axis of said cylinder ofrevolution
 4. For use in a phototypesetting machine or the like,character storage apparatus for storing characters for selectivepresentation at a character display location, comprising: a drumcomprising: a plurality of interchangeable, rigid, discrete drumsegments for receiving a like number of fonts strips, one on each drumsegment, hub means, and means for attaching said drum segments to saidhub means; and a number of discrete font strips equal to the number ofdrum segments each strip caRrying a font of characters; and means forattaching said font strips to said drum segments, one on each drumsegment, whereby said drum is capable of carrying desired combinationsof individually replaceable and accurately positioned character fonts,said font strips being positioned to place said characters in anunobstructed optical path through the rigid drum segments.
 5. Theapparatus defined by claim 4 including registration pin means on saidhub means and associated pin receiving openings in said drum segmentsfor minimizing positional variation of said drum elements transverse tosaid drum axis.
 6. The apparatus defined by claim 4 wherein said meansfor attaching said drum segments provides for attachment of said drumsegments to said hub means each independently of all others.
 7. Theapparatus defined by claim 4 wherein said means for attaching said fontstrips to said drum segments comprises an adhesive coating disposed oneach font strip in a pattern configured to avoid the characters on saidstrip.
 8. The apparatus defined by claim 6 wherein said means forattaching said font strips to said drum segments comprises an adhesivecoating disposed on each font strip in a pattern configured to avoid thecharacters on said strip.
 9. The apparatus defined by claim 4 whereinsaid hub means defines a radially extending mounting surface forreceiving said drum segments, wherein said drum segments each have aradially extending surface adapted to mate with said mounting surface onsaid hub means, and wherein said means for attaching said drum segmentsprovides for attachment of said drum segments to said mounting surfacewith substantially no play parallel to the axis of the drum whereby tooptimize the accuracy in an axial direction of the location of saidcharacters on said character storage apparatus.
 10. The apparatusdefined by claim 8 wherein said hub means defines a radially extendingmounting surface for receiving said drum segments, wherein said drumsegments each have a radially extending surface adapted to mate withsaid mounting surface on said hub means, and wherein said means forattaching said drum segments provides for attachment of said drumsegments to said mounting surface with substantially no play parallel tothe axis of the drum whereby to optimize the accuracy in an axialdirection of the location of said characters on said character storageapparatus.
 11. The apparatus defined by claim 4 wherein said drumsegments are composed of a transparent plastic material.
 12. Theapparatus defined by claim 10 wherein said drum segments are composed ofa transparent plastic material.
 13. The apparatus defined by claim 10wherein said drum segments are composed of a metallic material and haveopenings therein registered with said characters.